Spark plug adapter



Oct. 2, 1962 w. G. CLAYTON 3,056,899

SPARK PLUG ADAPTER Filed Nov. 25, 1959 40 Fig. 2

INVENTOR.

WILLIAM G. CLAYTON United rates Patent 3,656,899 SPARK PLUG ADAPTERWilliam G. Clayton, 865 Palomar, Chula Vista, Calif. Filed Nov. 23,1959, Ser. No. 854,673 Claims. (Cl. 313-443) The present inventionrelates generally to spark plugs and more particularly to a spark plugadapter.

The primary object of this invention is to provide a spark plug adapterwhich can be added to a slightly modified, conventional spark plug toproduce a plug having a generally cylindrical electrode, which allowsthe sparks to be distributed around the electrode instead of to a singlepoint, thereby eliminating pitting.

Another object of this invention is to provide a spark plug adapterhaving a cup portion in which the spark is contained and which holds apocket of relating static gases in the region of the spark to ensureproper ignition.

Another object of the invention is to provide a spark plug adapter of aconfiguration ensuring its proper functioning while also assuringagainst any possible damage to the ceramic element of the plug duringinstallation of the adapter or during the normal use of the adaptedplug.

Still another object of this invention is to provide a spark plugadapter having ventilating means through which the gases can circulatearound the electrodes and thus minimize fouling.

A further object of this invention is to provide a spark plug adapterwhich is easily yet securely attached to a spark plug with simple handtools.

It is a further object of this invention to provide a spark plug whichdisplays the advantages listed near the end of the specification.

Finally, it is an object to provide a spark plug adapter of theaforementioned character which is simple and convenient to install anduse and which will give generally efiicient and durable service.

With these and other objects definitely in view, this invention consistsin the novel construction, combination and arrangement of elements andportions, as will be hereinafter fully described in the specification,particularly pointed out in the claims, and illustrated in the drawingwhich forms a material part of this disclosure, and in which:

FIGURE 1 is a side elevation view of a spark plug fitted with theadapter;

FIGURE 2 is an enlarged fragmentary sectional view taken on the line 2-2of FIGURE 1;

FIGURE 3 is a sectional view taken on the line 3-3 of FIGURE 2;

FIGURE 4 is an end elevation view as taken from the lower end of FIGURE1;

FIGURE 5 is an enlarged fragmentary sectional view taken on the line 5-5of FIGURE 4; and

FIGURE 6 is a perspective view of the adapter.

Similar characters of reference indicate similar or identical elementsand portions throughout the specification and throughout the views ofthe drawing.

The spark plug it as illustrated, is of conventional type having ametallic body 12, at one end of which is a threaded portion 14 forinsertion into the usual spark plug bore, said threaded portion having adeep internal socket 16. Extending axially through the body 12 is arod-like central electrode 18 enclosed in a cylindrical insulatingjacket 20 of ceramic or similar material, said insulating jacketprojecting from the other end of said body and having an end terminal 22thereon connected to said electrode. The insulating jacket 20 has atapered portion 24 extending into the socket 16, the electrode 18 prohcejecting beyond the tapered portion. Normally, the electrode 18 isprovided with a radially extending tongue 26, indicated in broken linein FIGURE 1, the spark jumping between said tongue and the rim of thecentral electrode 18. In the present embodiment, however, the tongue 26is cut off and the electrode 18 finished with a flat end 28 generallyplanar with the end of the threaded portion 14 and concentric with thesocket 16.

The adapter 30 is of generally cylindrical construction having a sleeveportion 32, which is a close fit inside the socket 16, and an enlargedend 34, providing a shoulder 36 which rests on the end face 38 of thethreaded portion 14. The enlarged end 34 has a generally conical cup 40therein, converging to an electrode collar 42 having an axially parallelwall concentric with the central electrode 18 and radially aligned withthe flat end 28. The sleeve portion 32 has a tapered inner bore 44diverging from the electrode collar 42 and concentrically spaced fromthe tapered portion 24.

. The adapter 30 is provided with a plurality of vents 46, four beingindicated as an example, each vent extending from the outer wall of theenlarged end 34 to the interior of the tapered inner bore 44 andbypassing the cup 40 and electrode collar 42. The vents 46 extend acrossthe shoulder 36 and provide clearance over the peripheral edge of thesocket 16 at said shoulder. The adapter 30 is locked in place by meansof a plurality of small indentations 48 in the outer face of the sleeveportion 32 adjacent the shoulder 36. With the adapter held in the socket16, portions of the end face 38 are peened into the indentations 48, asindicated at 50. This may be accomplished with a common punch and hammeror by any other suitable tool, the material from which the body 12 ismade normally being soft enough to allow such deformation. To facilitatethe peening operation, the indentations 48 are preferably disposedsymmetrically between the vents 46, said vents thus serving as guides tothe location of the indentations for positioning the punch or otherpeening tool.

In operation in an internal combustion engine, the sparks jump betweenthe central electrode 18 and the surrounding electrode collar 42, at anyposition. Since the sparks are thus distributed around the electrodecollar 42, there is no concentration of pitting or burning at anyparticular spot, resulting in extended electrode life. The cup 40 tendsto hold an accumulation of explosive gases in immediate proximity to thespark, thus ensuring proper ignition. Due to the vents 46, the gases cancirculate through the vents, in the socket 16 and between and around theelectrode structure to prevent overheating and to prevent fouling.

While the vents 46 are preferable, certain types of engines operate atrelatively low temperatures and, for such engines, the adapter may bemade without vents at a reduced cost, while retaining all the otheradvantages of the structure. In the vented adapter, any number of ventsmay be used according to size and specific requirements.

While the adapter 30 is specifically intended for instal- =lation inexisting spark plugs, modified by removal of the radially extendingelectrode tongue, it should be understood that the novel constructioncan be incorporated as part of the basic structure of a spark plug. Asan addition to conventional spark plugs, the adapter offers greatlyextended plug life at low cost, since the electrode element normallyshowing the greatest wear is removed when installing the adapter, thebasic plug structure usually having a useful life well in excess of theelectrodes. The adapter is thus applicable to used spark plugs whichwould normally be discarded, as well as offering improved performancefrom new or relatively new plugs.

Advantages claimed for this spark plug include the features that it isnon-fouling, capable of operating at the optimum spark gap with optimumspark size according to changing conditions of voltage, differential,temperature and pressure within the cylinder, elimination of manualspark gap adjustment, and smooth operation of the motor. Long sparksalso jump between the fiat end 28 of the electrode 18 and the adjacentinner surface of the cup 34. It should be noted, in this regard, thatthe taper of the cup may be altered consider-ably from that illustratedin the drawing or may be deleted and the inner surface maderecti-cylindrical.

The operation of this invention will be clearly comprehended from aconsideration of the foregoing description of the mechanical detailsthereof, taken in connection with the drawing and the above recitedobjects. It will be obvious that all said objects are amply achieved bythis invention. I

It is understood that minor variation from the form of the inventiondisclosed herein may be made without departure from the spirit and scopeof the invention, and that the specification and drawing are to beconsidered as merely illustrative rather than limiting.

I claim: 7

1. In combination: a spark plug having a body; said body having athreaded portion for insertion into a spark plug receiving bore and aninternal socket in said threaded portion; a central electrodeconcentrically mounted in said socket; an adapter fixed in said sparkplug; said adapter having a sleeve portion fitting closely into saidsocket; an enlarged end on said adapter having a shoulder engaging theend face of said threaded portion; an internal electrode collar in saidadapter and concentrically spaced from said central electrode; and saidadapter having a plurality of circumferentially spaced vents thereincommunicating from the outside of said enlarged end adjacent saidshoulder to the inside of said sleeve portion within said socket; saidsleeve portion having a plurality of indentations in the outer surfacethereof adjacent said shoulder to receive deformations of said threadedportion, whereby said adapter is locked against displacement.

2. In combination: a spark plug having a body; said body having athreaded portion for insertion into a spark plug receiving bore and aninternal socket in said threaded portion; a central electrodeconcentrically mounted in said socket; an adapter fixed in said socketof said spark plug; said adapter having a sleeve portion fitting closelyinto said socket; an enlarged end on said adapter having a shoulderengaging the end face of said threaded portion; an internal, annulargrounded electrode collar in said adapter and concentrically spaced fromsaid central electrode; said electrode collar having a tapered cupdiverging toward the outer end of said adapter; said sleeve portionhaving a tapered inner bore diverging from said electrode collar; andsaid adapter having a plurality of circumferentially spaced ventstherein communicating from the outside of said enlarged end adjacentsaid shoulder to said tapered inner bore.

3. In combination: a spark plug having a body; said body having athreaded portion for insertion into a spark plug receiving bore and aninternal socket in said threaded portion; a central electrodeconcentrically mounted in said socket; an adapter fixed in said sparkplug; said adapter having a sleeve portion fitting closely into saidsocket; an enlarged end on said adapter having a shoulder engaging theend face of said threaded portion; an internal electrode collar in saidadapter and concentrically spaced from said central electrode; saidelectrode collar having a tapered cup diverging toward the outer end ofsaid adapter; and said adapter having a plurality of circtunferentiallyspaced vents therein communicating from the outside of said enlarged endadjacent said shoulder to the inside of said sleeve portion within saidsocket; said sleeve portion having a plurality of indentations in theouter surface thereof adjacent said shoulder to receive deformations ofsaid threaded portion, whereby said adapter is locked againstdisplacement; said indentations being circumferentially spacedsubstantially symmetrically between said vents.

4. A spark plug and adapter combination according to claim 1, whereinsaid central elect-rode has a flat end substantially planar with the endface of said threaded portion.

5. An adapter for a spark plug of the type having an externally threadedsocket and an axially disposed central electrode, said adaptercomprising: a sleeve portion; means to secure said sleeve portion insaid socket, axially thereof and spaced from said electrode, saidsecuring means comprising a plurality of circumferentially spacedindentations in the exterior surface of said sleeve portion, and anexternal shoulder on said sleeve portion adjacent to said indentations,whereby the shoulder may be employed as a stop to limit insertion of thesleeve portion into said externally threaded socket and thus tofacilitate location of said indentations adjacent to the end of theexternally threaded socket; said sleeve portion having an internal,annular electrode collar encircling said central electrode, whereby anannular spark gap is defined between said electrode collar and saidcentral electrode.

References Cited in the file of this patent UNITED STATES PATENTS1,338,674 Champion May 4, 1920 1,929,748 Little Oct. 10, 1933 2,029,669Nowosielski Feb. 4, 1936 2,127,513 Harper Aug. 23, 1938 2,266,999 SmithDec. 23, 1941 FOREIGN PATENTS 565,715 France Nov. 10, 1923

